A detailed case that the New Testament Epistle of Jude was written against the socalled Cainite sectaries, who were in possession of a Gospel of Judas as Irenaeus attests is presented here. Because the names Judas and Jude were the same, the good name of Iouda, especially as being that of a relative to Jesus, needed clearing, and subversive teachings — making Cain, Judas and other Biblical figures worthy opponents of the (Old Testament) god — had to be combatted. Since a Gospel of Judas has come to light, within the newly published Tchacos Codex, one is challenged to decide whether this was the gospel appealed to by the Cainites, and, if it was, to begin to grasp how they read a text which did not readily match their interests.